Varied volatile compounds are produced by Propionibacterium freudenreichii in Emmental cheese

The role of propionibacteria in the volatile profile of Pategrás cheeses

“…On the other hand, values of pH, fat matter, moisture, protein, salt content, and ripening degree did not show statistical differences (P > 0.05) between cheeses R and E. Thus, the gross composition of Pategrás made at pilot scale was not influenced by the addition of PAB. Similar results were reported by Thierry et al (2004aThierry et al ( , b, 2005a in Emmental and Raclette cheeses.…”

“…For each compound, mean values ± standard deviations (SD) and range of values (minimum and maximum values) were also included. All these compounds have been already reported in different varieties of cheeses containing PAB (Bosset et al 1993;Thierry et al 1999Thierry et al , 2004aThierry et al , 2005aThierry et al , b, 2006Rychlik and Bosset 2001a, b;Mallia et al 2005). Figure 1 shows the relative percentages of the different chemical groups calculated with respect to the total content of identified compounds.…”

“…2-Methylpropanoic and 3-methylbutanoic acids were also identified in all samples, being a minority fraction. The preponderance of acids and the high levels of propanoic acid have been extensively reported in cheeses containing PAB (Engels et al 1997;Thierry et al 2004aThierry et al , 2005a. Short-chain fatty acids and some branched-chain fatty acids such as 2-and 3-methylbutanoic are those most likely involved in Swiss-type cheese flavor (Bosset et al 1993;Thierry et al 2004b).…”

“…In particular, the levels of NaCl had an important effect on the growth of PAB. It has been reported that high salt-in-moisture contents can delay PAB growth and decrease the volatile fatty acid content, methylbutyric acid formation, and CO 2 production (Richoux et al 1998;Thierry et al 2004aThierry et al , b, 2005a. However, this inhibiting effect is strain dependent.…”

“…Short-chain fatty acids and some branched-chain fatty acids such as 2-and 3-methylbutanoic are those most likely involved in Swiss-type cheese flavor (Bosset et al 1993;Thierry et al 2004b). PAB are known to ferment lactic acid to acetic and propanoic acids, but more recently it was shown that they play a key role in the formation of free fatty acids from lipolysis of the milk fat or branched-chain fatty acids from leucine or isoleucine catabolism (Thierry et al 2004a).…”